Magnesium alloys



Patented Feb. 10, 1942 MAGNESIUM ALLOYS Alfred Diillenbach, Ruschlikon; Zurich, Switzerland, assignor to Arnold Hammer, Zurich,

Switzerland No Drawing. Application December 13, 1939, Se-

rial No. 309,100. In Switzerland December 14,

2' Claims.

The present invention relates to the production of magnesium alloys and has for its object to provide a magnesium alloy which is suflicient- 1y resistant against corrosion and has a hardness permitting the alloy to be ,used for industrial purposes.

Repeated but "unsuccessful attempts have hitherto been made to produce magnesium alloys having the above mentioned properties. To raise the hardness of such alloys it has already been proposed to use magnesium alloys containing silicium and relatively high percentages of aluminium and containing furthermore the metals stiblum, nickel, chromium, manganese and molybdenum as hardening agents. To reduce their brittleness these alloys must further contain copper and titanium.

Thus the aforementioned alloys are composed of ten components. a fact that makes the production of homogenous melts very difflcult due to the fact that the components separate from the melts when they are cooled.

Experience in practice has shown that in most cases it is quite impossible to obtain homogenous alloys with the components enumerated above and that the magnesium content should not substantially exceed 60% if a suflicient Brinell hardness of about 100 is to be obtained.

V The object of the present invention. therefor is to provide a magnesium alloy with a much simpler composition. which in suite of its hi h magnesium contents shows a Brinell hardness of 100-125 although it does not contain the c mnonents silicon. stibium, nickel, chromium, molybdenum and titanium.

The new alloy according to the present invention is characterised by the fact that it contains only magnesium. aluminium, cop er. manganese, silver and either beryllium. i idium or tantalum :in the proportions of 70-30% Me. 10452. A1. 740% Cu. 1-22J1vm and 24% Ag and 0.5-1% of beryllium. iridium or tantalum. The purpose of the beryllium. iridium and tantalum is to obtain an especially hi h Brinell hardness and 2-3% of iron. particularly grey cast iron, may be included for improving the machining, rolling and harding properties.

It is evident, that it is much'easier to produce this alloy on a technical scale than the alloys mentioned above, due to the fact that the number of the components is not chosen higher than strictly necessary to obtain the desired effect, and that the silver has a compensating and homogenizing efiect so as to avoid the separation of particular components when the alloy is cooled. The following are some typical examples of alloys within the scope of the present invention:

F r 1 Per cent Mg- 75.1 1 Al 12.4

5 Cu 7.5 Mn 20 Ag 20 Be H Per cent Mg 75.2 A1 12.3

Cu 1.0 Mn 1.0

Cu 7.2 Be 0.6 Ag

111 Per cent Mg 72.2 M 12.2 Cu 7.7

Mn 1.9 A2 2.5 Be 1.0 25 Fe 2.5

These alloys have a specific weight of between 1.9 and 2.1 and a small coefllcient of expansion,

sentially of about 10 to 15% aluminium, about 7 7'to 10% manganese, about2 to 3% silver as a homogenizer during cooling, about 0.5 to 1% of a metal of the group consisting of beryllium, iridium and tantalum, and substantially all of the balance being magnesium,- said alloy being substantially free of silicon, stibium, nickel, chromium, molybednum and titanium.

2. A homogeneous alloy which has a Brinell hardness of about 100 or higher, a specific weight of between about 1.9 and 2.1, a low coeificient of expansion, low coeiiicient of friction and high heat conductivity consisting of about 10 to 15% aluminium, about 7 to 10% manganese, about 0.5 to 1% of a metal of the group consisting of beryllium, iridium and tantalum, about 2 to 3% silver as a homogenizer, and substantially allot the balanc being magnesium.

. ALFRED DKLLENBACH. 

